The present invention relates to counter-rotating means for marine vehicles. Representative examples of the art in this area appear in U.S. Pat. Nos. to Kirsch 155,192 (1874), Baker, 480,225 (1892), and Miller 2,777,414 (1957).
Most patents in this field relate primarily to paddle wheel vessels which, for the most part, have not been commercially viable for over fifty years. Their main relevancy to the present invention lies in their suggestion of a dual counter-rotating propeller mechanism.
The present invention moves beyond the above-mentioned counter-rotating feature in that it provides as its counter-rotating element a pair or gang of spinwheels having a plurality of blades which, by virtue of a novel camming arrangement, are extended and retracted in a manner which sharply reduces the dead-water drag upon the dual counter-rotating elements.
The prior art with regard to a reciprocating paddle arrangement includes U.S. Pat. Nos. to May, 22,884 (1859); Burger, 678,938 (1901); and Ferraguto, 1,869,136 (1932).
The weakness in the paddle retraction systems disclosed in these said patents lies in their functional complexity and lack of durability.
Accordingly, the present invention may be viewed as a means for providing an improved camming system that would enable such prior art as has been above enumerated to fulfill much of the technical promise which it, at one time, had enjoyed.